A copy of a final tibia prosthesis designed to be used during unicompartmental knee replacement surgery or total knee arthroplasty (TKA) to determine the correct alignment, size, and fit of the final prosthesis. It is one of a set of trial knee prostheses that match the different anatomical structures of the knee joint, and may be used in conjunction with a knee femur trial prosthesis and a patella trial prosthesis. It is typically made of metal or polymer material and includes tibial base plate trials, tibial spacer trials, tibial insert trials, tibial wedge/augment trials, and guide pin trials. This is a reusable device intended to be sterilized prior to use.